Most wiki software offers two choices of markup when formatting content. Typically, most of them allow HTML markup, but more importantly they offer a special markup such as that of MediaWiki, or some equivalent to BBCode which is the de facto standard used across the most common forum softwares.
In nearly every case (with a major exception being templates), you should opt to use wiki markup rather than HTML markup. One of the key principles behind massive-collaboration engines such as MediaWiki, is that content should be easy to edit and format by anyone, including (quite especially) those untrained in HTML markup. I have heard some argue in favor of embedded WYSIWYGs for wikis – I am perhaps a bit more old-fashioned, but I have not yet formed a solid opinion one way or the other on this. I may address it in a future post.
In short, this means you should opt for using wiki markup to create tables, lists, and formatted text rather than HTML in most cases. As well, you should opt for the following (assuming MediaWiki):
'''Strong''' ''Emphasis'' *Unordered List Item 1 *Unordered List Item 2 #Ordered List Item 1 #Ordered List Item 2 [[Internal Link|Internal Link Text]] [External Link External Link Text]
Rather than:
<strong>Strong</strong> <em>Emphasis</em> <ul> <li>Unordered List Item 1</li> <li>Unordered List Item 2</li> </ul> <ol> <li>Ordered List Item 1</li> <li>Ordered List Item 2</li> </ol> <a href="">Internal Link Text</a> <a href="">External Link Text</a>
MediaWiki provides a complete Help document for Formatting.
